As is known in the art, a toll road is a road on which an agency (either a private agency or a public agency) collects money from users who wish to drive vehicles on the road. Typically, users pay a toll at so-called toll booths located at toll plazas which are established at certain locations along the road. The tollbooths sometimes include a gate which prevents a vehicle from passing through the toll booth unless a toll is paid. Once the toll is paid, the gate is raised to allow the vehicle to pass. Thus, to pay the toll at the tollbooth, the driver typically slows down the vehicle (or stops the vehicle if the toll booth has a gate) at the tollbooth and either pays a person acting as a toll collector or deposits money in a collection bin which registers payment of the toll.
As is also known, there is a trend on toll roads to automate the collection of the toll. Some automated toll collection systems allow electronic payment of the toll. To allow such automated electronic toll payment, users who wish electronically pay the toll place a transponder in their vehicle (sometimes referred to as a “toll transponder”). The vehicle transponder communicates with one or more reader systems which are mounted at predetermined locations (typically at toll plazas) along the toll road. Such automated toll systems do not require any gates, barriers or any physical impediments to free traffic flow on the highway. With this technique, tolling can be accurately and reliably conducted substantially at highway speeds (i.e. vehicles having transponders mounted therein need not slow down significantly for the toll to be collected).
In particular, on certain roadways, single occupancy vehicle (SOV) users are permitted to use the high occupancy toll (HOT) lanes if they use a Dedicated Short Range Communications (DSRC) transponder (also sometimes referred to as a toll transponder) to pay the appropriate toll posted at a toll gate which may, for example, be located at the vehicle's point of entry on the road. Thus, automatic toll collection systems do not require any toll plazas, gates, barriers or any physical impediments to free traffic flow on the highway. Furthermore, tolling can be accurately and reliably conducted at or near highway speeds.
It is possible, however, for an SOV driver to use the HOV lane but to either not have an approved transponder, or to hide or shield the transponder to avoid having the toll collected. It would, therefore, be desirable to provide a system and technique which can detect these situations.